AU2828001A

AU2828001A - Lifting jack

Info

Publication number: AU2828001A
Application number: AU28280/01A
Authority: AU
Inventors: Detlef Struck
Original assignee: Columbus McKinnon Industrial Products GmbH
Current assignee: Columbus McKinnon Industrial Products GmbH
Priority date: 1999-12-13
Filing date: 2000-12-02
Publication date: 2001-06-25
Anticipated expiration: 2020-12-02
Also published as: CZ291908B6; CZ20012915A3; ATE271017T1; ZA200106542B; ES2222274T3; BR0008168A; EP1150916B1; US20020027222A1; AU759668B2; CN1148314C; WO2001044100A1; PL202461B1; CA2363082A1; KR100417577B1; HK1046126A1; TW555686B; DE50007068D1; CA2363082C; PL349263A1; DE19959999C2

Abstract

The invention relates to a lifting device with a housing having a drive wheel, a friction disk brake, a load wheel and a gear arranged sequentially in an axial direction inside the housing. The drive shaft extends through the friction disk brake and the load wheel. A torque is transmitted from the drive wheel to the load wheel. The drive wheel cannot move axially on the drive shaft, but can rotate over a limited range relative to the drive shaft. The drive wheel can rotate in a limited fashion relative to a brake disk, which is axially moveable on a threaded section of the drive shaft and can be pressed with the help of a friction disk against a pressure disk that is attached to the housing. The drive wheel forms a component of the friction disk brake.

Description

Lifting device The invention concerns a lifting device according to the features of the generic part of claim 1. 5 Lifting devices of the type discussed here are used in particular for the vertical displacement of loads. They comprise a driving wheel that is often constructed as a chain wheel and can be rotated in both directions by means of a manually operated round link chain. Instead of a chain wheel the driving wheel can be 10 constructed as a clutch wheel to a motor shaft. The load wheel, that is also often constructed as a chain wheel, is joined to a load lifting means, like a crane hook, by means of a round link chain. 15 As a rule, the housing of the lifting device has a hook, by means of which it can be suspended on suitable supports. Arranged axially and consecutively, the driving wheel, a load pressure brake, the load wheel and a gear box are provided in the housing, while the gear box is often constructed as a planetary drive. The driving wheel is provided at one end of a drive shaft that passes through the load 20 pressure brake and the load wheel. At the other end of the drive shaft the gear box is located, which is connected in a torque-transmitting manner with the load wheel. In the case of a known construction of an above described lifting device 25 (pamphlet by the Yale Industrial Products GmbH, 5620 Velbert 1 "Yale Flaschenzug/Hand hoist/Palan A bras Mod.VS") the load pressure brake is made up from a ratchet wheel, two friction discs situated on both sides of the ratchet wheel as well as from two pawls hinged on the housing, which under the infkence of lever springs are pressed against the ratchet wheel. Both friction 30 iscs enter into a friction-locked connection with the ratchet wheel on the one hand and a pressure disc and the driving wheel fastened on the shaft, on the other. The driving wheel can be axially displaced on a thread at one end of the drive shaft. The other end of the drive shaft is connected with two gears, which in turn are connected with a gear via a pinion having a smaller diameter, the latter gear having internal teeth engaged by a pinion that is connected with the load wheel. The task of the load pressure brake is to hold the load carried by the lifting device 5 at the respective height when the driving wheel is at standstill. In that case the driving wheel is pressed against the pressure disc via the friction gfiscs and the ratchet wheel. The pawls engage the circumferential recesses f the ratchet wheel. 10 When the driving wheel is rotated in the direction of lifti., the pawls slide over the teeth of the ratchet wheel until the driving wheel sps. Then the pawls engage again the recesses of the ratchet wheel. W en the load is lowered, the driving wheel is rotated in the opposite direction, onsequently it will axially slide on the movement thread of the drive shaft and he friction-locking contact with the 15 friction discs, ratchet wheel and pressure dig6 will be terminated. The load can be lowered until the shaft compensates agai for the axial clearance. In the case of the known construction he fact, that the load pressure brake can fail when foreign bodies penetrate 0'r when the coil springs brake, has shown 20 itself as worthwhile improving. Tpe noise of the ratchet wheel is also undesirable in many cases, especially whe these noises are annoying. Furthermore, the manufacture of the load pre ure brake is expensive, while the manufacturing cost of the ratchet wheel i of particular note. 25 Based on the state-of/the-art the object of the invention is to produce a lifting device that has a sjpler construction, is less sensitive to interference and works more quietly. This objective is achieved according to the invention by the features stated in the 30 characterising part of claim 1. According to them, although the driving wheel can have a limited rotation relative to the drive shaft, it cannot, however, be displaced axially. In addition, the driving wheel is coupled with a limited relative rotatability with a brake disc, that in turn is axially displaceable on the threaded portion of the drive shaft. Between the brake disc and a pressure disc fastened on the housing of the lifting device a friction disc is situated. 5 Should a load need to be lifted, the driving wheel is rotated clockwise. After a predetermined angle of rotation, through which the driving wheel can freely rotated relative to the drive shaft, the free rotating movement is terminated and the drive shaft is driven directly by the hand wheel without a load applied to the brake. By virtue of the right-hand threaded portion, when being rotated clockwise 10 the brake disc is disengaged from the friction disc, so that the braking effect is terminated. When the rotating movement of the driving wheel is stopped, the drive shaft, rotating under the influence of the load, pulls the brake disc against the friction 15 disc and consequently against the pressure disc. The load is blocked. For the purpose of lowering the load, the drive shaft has to be rotated anticlockwise. After a predetermined angle of rotation the driving wheel will be coupled with the brake disc. Due to the right-hand threaded portion the brake disc 20 is axially displaced in the direction of the driving wheel and the contact with the pressure disc via the friction disc is terminated. Following this the load can drop corresponding to the predetermined angle of rotation between the driving wheel and the brake disc and it will be braked again due to the fact that the driving wheel rotating due to the load pulls the brake disc against the friction disc and 25 this, in turn, against the pressure disc. The particular advantage of the invention is that when compared with the known construction it operates considerably more accurately and more quietly. The lifting device according to the invention has a simpler construction also because 30 of the number of components. It can be further stated that the drive shaft and consequently the load wheel are directly driven by via the driving wheel without exerting a load on the load pressure disc.

As is the case for the state-of-the-art, the driving wheel can be driven by means of a chain, cable, crank or also by a motor. According to the features of claim 2, the rotatability of the driving wheel on the 5 drive shaft is preferably realised with the aid of a bush provided on the drive shaft. The bush can have a press fit on the drive shaft. According to the features of claim 3, the driving wheel interacts in a torque transmitting manner with a lobe disc non-rotatably connected with the drive shaft. 10 For this purpose the driving wheel has a protrusion ont6 face that after a predetermined angle of rotation of the driving wheel ,ontacts its corresponding stop on the lobe disc and thus carries with it in a stating manner the lobe disc and consequently the drive shaft. 15 By virtue of the lobe disc pushed in a rotatsbly fixed manner onto the drive shaft the position of the bush is also fixed on/the drive shaft. The lobe disc is preferably pushed6nto a serration at the end of the drive shaft and with the aid of a nut is pressed against the bush, that in turn is pressed 20 against a shoulder of the driv 'haft. The driving wheel is then accurately guided between this radial collar apd that face of the lobe disc which faces it. The lobe disc has at least one rad,Oily protruding lobe that interacts with at least one protrusion on the face the driving wheel. By virtue of the interaction of the protrusion with the I 9 e, the free rotatability of the driving wheel on the drive shaft 25 is limited. Thereup n the load can be raised via the driving wheel. The lobe disc has preferably o radial lobes offset at 1800 relative one another. Accordingly, in this case pref ably two protrusions are provided on the face of the driving wheel, in particular cast integrally with it, which interact with the lobes. 30 The co pling of the driving wheel with the brake disc with a limited rotatability is preferably realised by the features of claim 4. According to that an axially oriented driving pin is provided on the brake disc at a radial distance from the drive shaft. The driving pin engages a preferably arch-shaped curved segment-like recess in that side of the driving wheel which faces the load wheel. The ends of the recesses, engaged by the driving pin, are constructed as radially aligned webs. The driving of the brake disc by the driving wheel is used for lifting the brake disc off the pressure disc during the lowering of the load and consequently for the releasing of the load pressure brake. 5 According to claim 5, in a development of the basic idea of the invention the brake disc is pressed against the pressure plate by a spring, resting on the driving wheel. The main task of this spring is to produce an initial braking torque. By virtue of this the response time of the load pressure brake can be reduced. 10 The invention is explained in detail in the following based on an embodiment illustrated in the drawings. They show in: 15 Fig.1 - a top view of the lifting device, Fig.2 - a vertical longitudinal section along line Il-Il through the illustration of Fig.1, 20 Fig.3 - a vertical cross-section along line l1l-Ill through the illustration of Fig.1, and Fig.4 - a front view on the illustration of Fig.1 in the direction of arrow IV, without the lid. 25 The numeral 1 describes a lifting device in Figs.1 to 4, that is used for lifting and lowering of loads L. The lifting device 1 has a driving wheel 2, a load pressure brake 3, a load wheel 4 30 and a gear box 5 axially and consecutively arranged inside a housing G, not described in detail. The driving wheel 2 is provided at one end 6 of a drive shaft 7 and by means of this drive shaft 7, that passes through the load pressure brake 3 c R, and the load wheel 4, can be connected in a torque-transmitting manner with the Arr Y gear box 5 situated at the other end 8 of the drive shaft 7 and driving the load wheel 4. At that end 6, which carries the driving wheel 2 in the form of a chain wheel for a 5 round link chain (not illustrated), the drive shaft 7 has a cylindrical longitudinal portion 9 (Fig.2), that merges towards the face into a serration 10 and from the serration 10 into a threaded portion 11 at the end. A bush 13, having a radial collar 12, is placed on the cylindrical longitudinal portion 9 and pushed up to a shoulder 14 of the drive shaft 7. With the aid of a lobe disc 15 the bush 13 is 10 pushed against the shoulder 14, in fact by turning a nut 16 on the threaded portion 11, thus pressing the lobe disc 15 against the bush 13 and this against the shoulder 14 (Figs.1, 2 and 4). The lobe disc 15 can be recognised especially from Fig.4. It has a central annular 15 body 17, on which two radially protruding lobes 18, offset at 180* relative one another, are provided. Each lobe 18 has an arch-shaped curved rear region 19 and a stop surface 20, extending in a radial plane. The stop surfaces 20 of the lobes 18 come into contact with the protrusions 21 that are integrally formed on the free side 22 of the driving wheel 2. 20 The driving wheel 2 has an internal hub 23, with which it is slidingly guided between the radial collar 12 of the bush 13 and the opposite situated face 24 of the lobe disc 15 (Fig.2). 25 At that side 25 which is averted from the protrusions 21, the driving wheel 2 has three arch-shaped curved segment-like recesses 26 (Figs.2 and 3), which are bound by three radial webs 27. A carrier pin 28, provided in a brake disc 29 at a radial distance from the drive shaft 7, engages one of these recesses 26. By means of an internal thread 30 the brake disc 29 can be axially displaced on an 30 external thread 31 of the drive shaft 7. The internal thread 30 and the external thread 31 are right-hand movement threads. On that side which is averted from the driving wheel 2, the brake disc 29 has an annular construction and is in contact with a friction disc 32, that in turn is pressed against a pressure disc 33, that is fixed on the lateral plate 34 which forms a component of the housing (Fig.2). The abutment of the brake disc 29 against the friction disc 32 and of that against the pressure disc 33 is assisted by a coil compression spring 35, that passes over an axial stub 36 of the brake disc 5 29 and engages an annular recess 37 of the driving wheel 2. The lateral plate 34 of the housing G, carrying the pressure disc 33, together with a further lateral plate 38 arranged parallel to it at a distance, serves the purpose of rotary mounting of the load wheel 4, also constructed as a chain wheel for a 10 round link chain (Figs.1 and 2). The bearings for the load wheel 4 in the lateral plates 34 and 38 are designated by the numeral 39. The load wheel 4 is relatively rotatably mounted on two axially distanced from one another, cylindrical gliding surfaces 40 of the drive shaft 7. With an axial stub 41 the load wheel engages a gear 42, that sits non-rotatably on this stub 41 next to the lateral plate 38. 15 As this becomes obvious when considering Figs.1 and 2 in conjunction, the gear 42 meshes with two pinions 43, which are components of two gears 44, which, in turn, mesh with a gear portion 45 of the drive shaft 7. 20 Assuming that a load L has to be raised, the driving wheel 2 is rotated clockwise according to arrow PF of Figs.1, 3 and 4. Since first the driving wheel 2 can rotate freely on the bush 13 relative to the drive shaft 7, a rotation of the driving wheel 2 relative to the drive shaft 7 takes place, until the protrusions 21 abut against the lobes 18 of the lobe disc 15. As by means of the serration 10 the lobe disc 15 is 25 non-rotatably fixed on the drive shaft 7, now the drive shaft 7 will also be rotated clockwise in accordance with arrow PF. Consequently, a direct torque transmission is carried out from the driving wheel 2 to the load wheel 4, via the drive shaft 7 and the gear box 5. Due to the right-hand movement thread 30, 31 of the brake disc 29 and of the drive shaft 7, when rotating the driving wheel 2 30 clockwise according to arrows PF, the brake disc 29 lifts off the friction disc 32 according to arrow PF1 of Fig.2 and consequently the friction disc off the pressure disc 33. The load L can be raised without any braking effect.

When the driving wheel 2 is stopped, the suspended load L causes a rotation of the load wheel 4 in the direction of arrow PF3, therefore anti-clockwise, and consequently also a rotation of the drive shaft 7. Due to this the brake disc 29 is pulled in the direction of arrow PF2 against the friction disc 32 and the friction 5 disc against the pressure disc 33. The load L is fixed at this height (Figs.1-4). Should the load L need to be lowered, the driving wheel 2 is rotated anti clockwise in the direction of arrow PF3 of Figs.1-4. After a predetermined angle of rotation the driving pin 28 comes into contact with a web 27 of the driving wheel 10 2, so that now the brake disc 29 is also displaced on the movement thread 31 of the drive shaft 7 and is lifted off the friction disc 32 and that off the pressure disc 33. The load L then causes a rotation of the drive shaft 7 relative to the driving wheel 2, so that the brake disc 29 is pulled again against the friction disc 32 in accordance with arrow PF2 and thus against the pressure disc 33, and the load L 15 will be braked.

CR<

List of reference numerals 1 Lifting device G Housing 2 Driving wheel L Load 3 Load pressure brake PF Arrow 4 Load wheel PF1 Arrow 5 Gearbox PF2 Arrow 6 End of 7 PF3 Arrow 7 Drive shaft 8 End of 7 9 Cylindrical length portion of 7 10 Serration on 6 11 Threaded portion on 6 12 Radial collar of 13 13 Bush 14 Shoulder on 7 15 Lobe disc 16 Nut 17 Annular body of 15 18 Lobe of 15 19 Rear region of 18 20 Stop surface 21 Protrusions on 2 22 Side of 2 23 Hub of 2 24 Face of 15 25 Side of 2 26 Recesses in 25 27 Web between 26 28 Driving pin on 29 29 Brake disc 30 Internal thread of 29 31 External thread of 7 32 Friction disc 33 Pressure disc 34 Lateral plate 35 Coil pressure spring 36 Stub of 29 37 Annular recess in 2 38 Lateral plate 39 Bearing for 4 40 Gliding surfaces on 7 41 Stub on 4 42 Gear 43 Pinion 44 Gears 45 Gear portion of 7 * -- *4q,\ -0j

Claims

1. A lifting device 1, that has a driving wheel (2), a load pressure bra)e (3), a load wheel (4) and a gear box (5) axially and consecutively arrange#iinside a 5 housing, wherein the driving wheel (2) provided at one end (6 of a drive shaft (7) can be connected in a torque-transmitting manner witiy4he gear box (5) situated at the other end (8) of the drive shaft (7) and driving the load wheel (4) by means of this drive shaft (7), that passes throughfthe load pressure brake (3) and the load wheel (4), characterised in that the'driving wheel (2) is so 10 mounted on the drive shaft (7) that it cannot befdisplaced axially but can have a limited rotation relative to the drive shaft, and as a component of the load pressure brake (3) it can be relatively rotat&e to a limited extent together with a brake disc (29) that can be pressed agajst a pressure plate (33) fastened on the housing, which brake disc by incofforating a friction disc (32) can be 15 axially displaced on a threaded poron (31) of the drive shaft (7).

2. A lifting device according to cljm 1, characterised in that the driving wheel (2) is rotatably mounted on a brush (13) provided on the drive shaft (7). 20

3. A lifting device accordin to claim 1 or 2, characterised in that the driving wheel (2) has a protrusion (21) on its face that interacts in a torque-transmitting manner with a lob isc (15) non-rotatably connected with the drive shaft (7).

4. A lifting device ccording to any one of claims 1 to 3, characterised in that the 25 brake disc ( ) has an axially oriented driving pin (28) that engages a segment-li e recess (26) in that side (25) of the driving wheel (2) which faces the load heel (4).

5. A lifting device according to any one of claims I to 4, characterised in that the 30 brike disc (29) is pressed against the pressure plate (33) by a spring (35) resting on the driving wheel (2).